Heat dissipation device with heat pipe

ABSTRACT

A heat dissipation device includes a heat sink and a helical heat pipe assembly. The heat sink includes a hollow cylindrical body and a number of fins extending inwardly from an inner surface of the body to an axis of the body. The helical heat pipe assembly is wrapped on an outer surface of the body and helically extends along an axial direction of the body.

BACKGROUND

1. Technical Field

The disclosure relates to heat dissipation devices and, particularly, to a heat dissipation device with a heat pipe.

2. Description of Related Art

Heat dissipation devices are increasingly used in electronic products. A conventional heat dissipation device includes a base contacting a heat generating device, a plurality of parallel fins protruding from a top surface of the base and a heat pipe. In operation, the heat generated from the heat generating device is absorbed by the base and transferred by the fins. However, this conventional heat dissipation device has low heat dissipation efficiency.

In order to improve the heat dissipation efficiency of the heat dissipation device mentioned above, a heat pipe is applied to transfer the heat from the heat generating device to the fins. In detail, an evaporator section of the heat pipe is disposed between the bottom surface of the base and the heat generating device, and a condenser end of the heat pipe extends through the fins. In operation, the heat is quickly transferred by the heat pipe from the heat generating device to the fins, whereby the heat is dissipated out rapidly. Thus, the heat pipe plays a critical role during heat dissipation process. However, once the heat pipe is invalid or damaged, a heat dissipation efficiency of the whole heat dissipation device will be greatly degraded.

What is needed, therefore, is a heat dissipation device with a heat pipe overcoming the described limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an isometric, exploded view of a heat dissipation device in accordance with a first embodiment of the disclosure.

FIG. 2 is an assembled view of the heat dissipation device of FIG. 1.

FIG. 3 is an isometric, exploded view of a heat dissipation device in accordance with a second embodiment of the disclosure, showing an assembly of a heat sink and a plurality of heat pipes.

FIG. 4 is an isometric, exploded view of a heat dissipation device in accordance with a third embodiment of the disclosure, showing the heat dissipation device assembled on a printed circuit board.

FIG. 5 is the exploded view of the heat dissipation device of FIG. 4, viewed from a different angle.

DETAILED DESCRIPTION

Referring to FIG. 1 and FIG. 2, a heat dissipation device in accordance with a first embodiment includes a heat conducting base 10, a heat sink 20, a heat pipe assembly 30 and a fan 40. The heat conducting base 10 is made of heat conducting material, such as copper, aluminum, or the like. The heat conducting base 10 includes a top surface 12 thermally connecting with the heat pipe assembly 30, and a bottom surface 14 thermally contacting a heat generating device (not shown). The top surface 12 is curved corresponding to a curve of the heat pipe assembly 30.

The heat sink 20 is a unitary structure made from a metal block and includes a hollow cylindrical body 22, and a plurality of fins 24 extending inwardly from an inner surface of the body 22 toward an axis of the body 22. The fins 24 each have a first end connected to the inner surface of the body 22 and a terminal second end opposite to the first end. Each of the fins 24 is a wedge-shaped plate, and has a thickness gradually decreasing from the first end to the second end thereof. The first ends of the fins 24 are evenly arranged on a circumference of the inner surface of the body 22, and the second ends of the fins 24 cooperatively define an aperture 200. The second ends of the fins 24 may be free and spaced from each other or be connected to each other. A plurality of air flow paths 240 is defined by adjacent fins 24. In the illustrated embodiment, the second ends of the fins 24 are spaced from each other, and the air flow paths 240 extend inwardly from the inner surface of the body 22 and communicate with the aperture 200. Each air flow path 240 has a width gradually decreasing along a corresponding radial direction from the inner surface of the body 22 to the aperture 200.

Being arranged on the circumference of the inner surface of the body 22 and extending inwardly from the inner surface of the body 22, the fins 24 simultaneously transfer heat of the whole annular inner surface of the body 22 from the first end to the second end thereof along various directions. Then the heat at the second ends of the fins 24 can be quickly dissipated by air flowing through the air flow paths 240. Therefore, the illustrated structure of the heat sink 20 can dissipate the heat absorbed thereby quickly and efficiently.

Alternatively, the heat sink 20 can be an assembled structure of the body 22 and the fins 24. For example, the fins 24 are included in a unitary fin structure. In detail, a metallic sheet is bent in sequence to form a zigzag or wave configuration including a number of wedge-shaped protrusions. Each protrusion constructs one fin 24. Thus, the desired unitary fin structure is obtained. Then the unitary fin structure is assembled on the inner surface of the body 22 by a bolt or a soldering manner, thereby obtaining the assembled heat sink 20 consisting of the body 22 and the fins 24.

Alternatively, the outer surface of the body 22 can protrude or be soldered with a number of fins to increase a heat dissipating area of the body 22. For example, a number of fins are formed on the outer surface of the body 22 and located between the turn 311 b of the heat pipe 311 and the heat pipe 313.

One or more heat pipe assembly 30 wraps the outer surface of the body 22 of the heat sink 20 to remove the heat from the annular outer surface of the body 22. The heat pipe assembly 30 has a helical structure obtained by curving one or more elongated flat-type heat pipe. A curvature radius of the helical heat pipe assembly 30 is equal to that of the outer surface of the body 22 to assure that the helical heat pipe can tightly combine with the outer surface of the body 22. In this embodiment, the helical heat pipe assembly 30 is soldered on the outer surface of the body 22. In order to improve heat exchange efficiency between the heat sink 20 and the helical heat pipe assembly 30, a thermal interface material is applied between the outer surface of the body 22 and the helical heat pipe assembly 30. In operation, the whole annular outer surface of the body 22 exchanges heat with the heat pipe assembly 30 and therefore the heat of the body 22 of the heat sink 20 can be quickly removed by the heat pipe assembly 30.

Alternatively, the outer surface of the body 22 of the heat sink 20 defines a groove to receive the heat pipe assembly 30 therein. The heat pipe assembly 30 can be partially or wholly embedded in the groove of the body 22. The groove facilitates the heat pipe assembly 30 being easily soldered on the body 22 and tightly combining with the body 22. The outer surface of the body 22 can define a helical groove to receive the helical heat pipe assembly 30 therein, or define a number of parallel grooves to receive a number of straight heat pipes therein.

It is understood that shapes, structures of the heat pipe assembly 30 and the outer surface of the body 22 can be varied, so long as the heat pipe assembly 30 surrounds the outer surface of the body 22.

In the illustrated embodiment, the helical heat pipe assembly 30 is formed by three elongated flat-type heat pipes 311, 312, 313. The pipe 311 includes multi-turns wrapping the body 22 of the heat sink 20. Adjacent turns of one of the three heat pipes 311, 312, 313 are spaced by the other two of the three heat pipes 311, 312, 313. In this embodiment, two adjacent turns 311 a, 311 b of the heat pipe 311 are spaced by the heat pipe 312 and the heat pipe 313. That is, the heat pipe 312 and the heat pipe 313 are sandwiched between the two adjacent turns 311 a, 311 b of the heat pipe 311. In this structure, a distance between the adjacent turns 311 a, 311 b of the heat pipe 311 is relatively long. That is, a section the heat pipe 311 between the adjacent turns 311 a, 311 b can have a relatively low curving degree, thereby avoiding capillary structures therein to be damaged during forming the heat pipe 311. In order to obtain a relatively high heat exchange efficiency, a length of the helical heat pipe assembly 30 is equal to that of the body 22 of the heat sink 20, whereby the heat pipe assembly 30 substantially contacts the whole outer surface of the body 22.

The fan 40 is mounted on the another side surface of the body 22 to generate an air flow in the axial direction of the body 22. The fan 40 includes a cylindrical frame 41 and a blade module 42 fixed to the frame 41. The blade module 42 includes a shaft 421 and several blades 422 extending outwardly from the shaft 421. The frame 41 is mounted to the body 22 with the shaft 421 of the blade module 42 corresponding to the aperture 200 and the blades 422 corresponding to the air flow paths 240. In heat exchanging process, a portion of air flows generated by the blades 422 flow in the air flow paths 240 along a lengthwise direction of the body 22, simultaneously, another portion of air flow congregates and flows in the aperture 200 along the axial direction of the body 22. By the two approaches, the air flow exchanges heat with the fins 24 and the inner surface of the body 22 of the heat sink 20 to take away the heat.

In assembly, the heat pipe assembly 30 is soldered to the outer surface of the body 22 of the heat sink 20. An assembly of the heat sink 20 and the heat pipe assembly 30 is mounted on the base 10 by soldering the heat pipe assembly 30 to the top surface 12 of the base 10. The fan 40 is mounted to the side of the body 22 of the heat sink 20 by a number of bolts.

Referring to FIG. 3, a heat dissipation device in accordance with a second embodiment is illustrated. The heat dissipation device of the second embodiment has a structure similar to the heat dissipation device of the first embodiment, differing only in that configuration of a heat pipe is different from that of the heat pipe assembly 30. The heat pipe includes a number of parallel straight heat pipes 300 disposed on the outer surface of the body 22 and surround the body 22. The straight heat pipes 300 are parallel to the axis of the body 22. Adjacent heat pipes 300 can be spaced from or adjoin each other.

Referring to FIG. 4 and FIG. 5, a heat dissipation device in accordance with a third embodiment is illustrated. The heat dissipation device has a structure similar to the heat dissipation device of the first embodiment, differing only in that the heat conducting base 10 is omitted. The body 22 (shown in FIG. 1) of the heat sink 20 includes a first side surface thermally contacting a heat generating device 120 and a second side surface opposite to the first side surface. Each of the fins 24 (shown in FIG. 1) has a flat surface coplanar with the second side surface of the body 22. The body 22 is directly mounted to a printed circuit board 110 supporting a heat generating device 120 thereon by a plurality of blots 130. The body 22 defines a plurality of threaded holes 221, and the printed circuit board 110 defines a plurality of through holes 111 corresponding to the threaded holes 221. The blots 130 extend through the second threaded holes 111 of the printed circuit board 110 and are threaded in the first threaded holes 221 of the body 22 to fasten the body 22 to the printed circuit board 110, thereby the flat surface of the fins 24 thermally contacting the heat generating device 120. It is understood that the flat surface cooperatively formed by all of the fins 24 can be concave or convex relative to the first side surface of the body 22, so long as the flat surface of the fins 24 easily and tightly thermally combines with the heat generating device 120. The fan 40 is fixed to the second first side surface of the body 22.

Regarding the heat dissipation device of the illustrated embodiment, the helical heat pipe assembly 30 surrounds the outer surface of the body 22 of the heat sink 20 and thermally contact the heat conducting base 10. Thus a large contacting area is obtained between the helical heat pipe assembly 30 and the body 22 of the heat sink 20, thereby a large heat exchange area between the heat pipe assembly 30 and the body 22 of the heat sink 20 being obtained. The fins 24 positioned in side of the body 22 define a number of air flow paths 240 to allow the air flow generated by the fan 40 flowing therethrough and takes away the heat of the heat sink 20.

It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the apparatus and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat dissipation device comprising: a heat sink comprising a hollow cylindrical body and a plurality of fins extending inwardly from an inner surface of the body to an axis of the body; and a helical heat pipe assembly wrapped on an outer surface of the body and helically extending along the axial direction of the body.
 2. The heat dissipation device of claim 1, wherein the fins each have a first end connected to the inner surface of the body and a terminal second end opposite to the first end, and wherein the second ends of the fins cooperatively define an aperture.
 3. The heat dissipation device of claim 2, wherein the second ends of the fins are spaced from each other.
 4. The heat dissipation device of claim 3, wherein the fins define a plurality of air flow path communicating with the aperture.
 5. The heat dissipation device of claim 4, wherein the helical heat pipe assembly is obtained by curving at least one heat pipe.
 6. The heat dissipation device of claim 5, wherein the helical heat pipe assembly comprises multi-turns wrapping the outer surface of the body of the heat sink, and wherein the multi-turns are spaced from each other.
 7. The heat dissipation device of claim 6, wherein the helical heat pipe assembly is formed by curving a first, second and third heat pipes, and adjacent turns of the first heat pipe are spaced by the second heat pipe and the third heat pipe.
 8. The heat dissipation device of claim 7, wherein the outer surface of the body of the heat sink defines a helical groove to receive the helical heat pipe assembly therein.
 9. The heat dissipation device of claim 8, wherein the helical heat pipe assembly is partially or wholly embedded in the groove of the body of the heat sink.
 10. The heat dissipation device of claim 4, wherein the heat dissipation device further comprises a fan comprising a frame and a blade module fixed to the frame, the blade module comprises a shaft and several blades extending outwardly from the shaft, the frame is mounted to a first side surface of the body with the shaft corresponding to the aperture and the blades corresponding to the air flow paths.
 11. The heat dissipation device of claim 10, wherein the body of the heat sink comprises a second side surface opposite to the first side surface, the second side surface is configured for thermally contacting a heat generating device.
 12. The heat dissipation device of claim 10, wherein the heat dissipation device further comprises a heat conducting base having a bottom surface for thermally contacting a heat generating device and a top surface thermally connecting with the helical heat pipe assembly.
 13. A heat dissipation device comprising: a heat sink comprising a tubular, cylindrical body and a plurality of fins extending inwardly from an inner surface of the body to an axis of the body, the fins each having a free end unconnected to the inner surface of the body, the free ends of the fins cooperatively defining an aperture communicating with two side surfaces of the body; a plurality heat pipes disposed on an outer surface of the body and surrounding the outer surface of the body; a fan mounted to one of the two side surfaces of the body.
 14. The heat dissipation device of claim 13, wherein the fins define a plurality of air flow paths communicating with the aperture.
 15. The heat dissipation device of claim 14, wherein the plurality heat pipes constructs a helical structure wrapping the outer surface of the body and helically extending a long an axial direction of the body.
 16. The heat dissipation device of claim 15, wherein the helical structure is formed by curving a first, second and third heat pipes and comprises a plurality of spaced turns wrapping the outer surface of the body, and wherein adjacent turns of the first heat pipe are spaced by the second heat pipe and the third heat pipe.
 17. The heat dissipation device of claim 14, wherein the heat pipes are parallel straight heat pipes disposed on a circumference of the outer surface of the body and extend along an axial direction of the body. 